At present, electronic display devices have been widely employed in various electronic appliances, such as a liquid crystal television, a liquid crystal display, a digital poster board, a laptop computer, a personal digital assistant (PDA), a mobile phone, a digital camera and an electronic book reader.
When viewing a flat display device laterally, a viewer will get an experience that the image displayed on the flat display device has been deformed. For example, as shown in FIG. 1, an image on the flat display device, which is viewed as a rectangle image from a front side, will be viewed as a trapezoidal compressed image from a lateral side. For some flat display devices that cannot be viewed from a front side thereof in use, for example, a rectangular semitransparent display device provided on a car windshield, an image on the display device viewed by a viewer is deformed, as shown in FIG. 2. In another example, for a non-flat display device, such as a flexible display device that is adhered to a curved wall, an image on the non-flat display device is viewed as distorted at any view angle. Because the image displayed by the display device is deformed in the above situations, the display effect of the display device is degraded.